A socket wrench is a conventional tool for screwing or unscrewing a screw or a nut. A socket wrench usually comprises a wrench handle and a set of socket heads of different sizes. One end of the wrench handle is pivotally mounted with a square head that can be turned freely at a given angle. The top of the socket head has a square hole for receiving the square head on the wrench handle, while the lower hole is fitted over a nut or screw head. A wrench handle is usually furnished with a number of socket heads of different sizes so as to fit screws of various sizes.
When using a conventional socket wrench, the socket head and the screw bolt are closely fitted to each other, and the square head on the wrench handle and the socket head are also fitted closely. Upon unscrewing a screw bolt that has been screwed very tight, or has been rusted because of being fixed in place for a long time, the conventional socket wrench handle has to be hit to turn it by using a hammer so as to obtain more hammering and turning force to loosen the screw bolt or nut. Likewise, when a screw bolt has to be screwed tightly with a conventional socket wrench, the handle of the wrench also has to be hit with a hammer in the last stage of turning the wrench. The requirement of hitting the conventional socket wrench handle is considered a drawback of the conventional socket wrench; further, the action of hitting the wrench handle with a hammer is hazardous.
In view of the aforesaid drawbacks of the conventional socket wrench, the inventor has developed this invention to improve the conventional socket wrench; i.e., the socket wrench according to the present invention has a built-in member to provide a hammering effect without using an external tool or force. This invention also provides an attachment assembly, which can be mounted on a conventional socket wrench to generate a hammering effect.
U.S. Pat. No. 1,722,652 to M. T. Archer discloses a wrench, which can provide a hammering or striking force, but it is considered different from the present invention. In Archer's disclosure, the handle and the jaw of the wrench are formed as one piece, a considerable big head portion, which takes a lot of space during working over a screw bolt or nut.
The socket wrench according to the present invention has a small head, movable at a given angle, and takes a very small space during operating over a screw bolt; therefore, it is different in structure from the aforesaid wrench.
U.S. Pat. No. 1,787,185 to L. D. Baird discloses a wrench, which is used for setting up and disconnecting the couplings that connect the adjoining sections of a string of sucker rods used in pumping oil wells. It is quite different in structure and use from the wrench of the present invention.
U.S. Pat. No. 3,157,074 to L. M. Durkee discloses hand operated impact wrench, of which the structure is different from that of the present invention aside from the large dimension thereof. Between the crank to exert force and the screw bolt to receive the impact force, there is a longer distance. The hammer arms and the hammer heads have formed a big disc portion over the screw bolt to be operated on; its gravity center must be unstable during operating, and therefore, it is deemd not an ideal and workable tool.
U.S. Pat. No. 3,366,187 to A. L. Von Tersch discloses an impact driver, which has to be hit on its head portion which a hammer, but the present invention is to eliminate or improves upon the use of such an external hammer. The structure of the Von Tersch impact driver is rather complicated, and the impact force is applied axially. the object of the present invention is improve the conventional socket wrench, or is to add an attachment assembly to a conventional socket wrench, both of which utilize nonaxially applied forces; therefore, the way of using the Von Tersch driver and the wrench according to the present invention is quite different.